大型矿浆搅拌槽挡板结构对矿浆浓度分布影响的研究
发布时间：2019-06-12 09:52
【摘要】：在选矿的浮选工艺中大型矿浆调浆搅拌槽调节着矿浆和药剂的快速、均匀混合,为浮选提供良好的条件,是浮选工艺必不可少的调浆搅拌设备。矿浆搅拌效果不仅与搅拌叶轮密切相关,还与搅拌叶轮的工作环境(即流体介质的种类)、搅拌槽结构和附件等装置有关。现阶段对矿浆搅拌效果的影响有很多研究,但对挡板附件形状结构、安装方式的研究较少。竖直挡板搅拌槽已作为一种经典的搅拌设备,而对倾斜挡板等特殊挡板结构研究相对较少。利用计算流体力学(CFD)理论和计算技术可以获得搅拌槽内宏观流动和微观湍流特性的详细信息,使得采用CFD方法对过程设备进行模拟设计、放大和优化成为可能,能够预测槽内不同操作条件下和不同构型的流体动力学特性,通用性良好。本文利用CFD有限元计算方法中的多重参考坐标系法(MRF)对搅拌槽内的流场进行模拟,从挡板形状结构、安装方式、叶轮转速等多因素对搅拌槽内的多相流流场进行分析,旨在改进挡板结构设计,改善流场分布特性,以增强叶轮的剪切性能,避免导致搅拌涡流,促进矿浆颗粒充分混合。通过仿真表明:在搅拌过程中叶轮周围流体会形成两个旋转相反的涡流,促进矿浆整体循环,叶轮周围矿浆搅拌剧烈,叶轮边缘流速最大。前倾直挡板比标准直挡板结构对多相流搅拌更有利;采用前倾直挡板结构搅拌后的理想混合区(浓度58%~62%)比例最高,当其前倾角为45°时理想混合区比例高达到88.48%,达到最优搅拌效果。在搅拌槽结构尺寸、矿浆浓度等相同的条件下,叶轮转速为30~35r/min时矿浆搅拌理想混合区(浓度58%~62%)比例较高,达到最优搅拌效果。矿浆粘度在0.003~0.015kg·s/m2理想矿浆浓度随着矿浆粘度的升高而升高;粘度在0.015~0.020kg·s/m2时理想矿浆浓度随着矿浆粘度的升高略微降低。
[Abstract]:In the flotation process of mineral processing, the large slurry mixing tank adjusts the rapid and uniform mixing of pulp and reagent, which provides good conditions for floatation and is an indispensable slurry mixing equipment in flotation process. The mixing effect of slurry is not only closely related to the stirring impeller, but also related to the working environment of the stirring impeller (that is, the type of fluid medium), the structure of the mixing tank and the accessories. At present, there are a lot of studies on the effect of pulp mixing, but there are few studies on the shape and structure of baffle accessories and installation methods. Vertical baffle mixing tank has been used as a classical mixing equipment, but the research on special baffle structure such as inclined baffle is relatively few. The detailed information of macro-flow and micro-turbulence characteristics in stirred tank can be obtained by using computational fluid dynamics (CFD) theory and computational technology, which makes it possible to use CFD method to simulate and design the process equipment, amplify and optimize the process equipment, and can predict the hydrodynamic characteristics of different operating conditions and different configurations in the tank, and has good generality. In this paper, the multi-reference coordinate system method (MRF) in CFD finite element method is used to simulate the flow field in the stirred tank. The multiphase flow field in the stirred tank is analyzed from the shape and structure of the baffle, installation mode, impeller speed and so on. The purpose of this paper is to improve the baffle structure design, improve the flow field distribution characteristics, in order to enhance the shear performance of the impeller, avoid causing mixing vortex, and promote the full mixing of slurry particles. The simulation results show that during the stirring process, the fluid around the impeller will form two rotating vortex currents, which will promote the overall circulation of the pulp, the slurry around the impeller will stir violently, and the velocity at the edge of the impeller will be the largest. The forward tilting straight baffle is more beneficial to multiphase flow stirring than the standard straight baffle structure, and the ideal mixing zone (concentration 58% 鈮，
本文编号：2497924
[Abstract]:In the flotation process of mineral processing, the large slurry mixing tank adjusts the rapid and uniform mixing of pulp and reagent, which provides good conditions for floatation and is an indispensable slurry mixing equipment in flotation process. The mixing effect of slurry is not only closely related to the stirring impeller, but also related to the working environment of the stirring impeller (that is, the type of fluid medium), the structure of the mixing tank and the accessories. At present, there are a lot of studies on the effect of pulp mixing, but there are few studies on the shape and structure of baffle accessories and installation methods. Vertical baffle mixing tank has been used as a classical mixing equipment, but the research on special baffle structure such as inclined baffle is relatively few. The detailed information of macro-flow and micro-turbulence characteristics in stirred tank can be obtained by using computational fluid dynamics (CFD) theory and computational technology, which makes it possible to use CFD method to simulate and design the process equipment, amplify and optimize the process equipment, and can predict the hydrodynamic characteristics of different operating conditions and different configurations in the tank, and has good generality. In this paper, the multi-reference coordinate system method (MRF) in CFD finite element method is used to simulate the flow field in the stirred tank. The multiphase flow field in the stirred tank is analyzed from the shape and structure of the baffle, installation mode, impeller speed and so on. The purpose of this paper is to improve the baffle structure design, improve the flow field distribution characteristics, in order to enhance the shear performance of the impeller, avoid causing mixing vortex, and promote the full mixing of slurry particles. The simulation results show that during the stirring process, the fluid around the impeller will form two rotating vortex currents, which will promote the overall circulation of the pulp, the slurry around the impeller will stir violently, and the velocity at the edge of the impeller will be the largest. The forward tilting straight baffle is more beneficial to multiphase flow stirring than the standard straight baffle structure, and the ideal mixing zone (concentration 58% 鈮，
本文编号：2497924
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